HAVANA The world stood at the brink of Armageddon for 13 days in October 1962 when President John F. Kennedy drew a symbolic line in the Atlantic and warned of consequences if Soviet Premier Nikita Khrushchev dared to cross it.

An anti-Castro militant, now elderly and being held in a Texas jail, warned the CIA months before the 1976 bombing of a Cuban airliner that fellow exiles were planning such an attack, according to a newly released U.S. government document.